I'm pretty new in using vdub mod, and i'm not sure what kind of audio tweaks are neccessary, but here is my problem:

I selected a stream and disabled the rest. When i preview the output, the audio is there, and it displays the size of the audio being processed and all. But when i actually hit save, under audio, it always says 0kb, and the file has perfectly fine video, but no audio.

It's surprisingly easy. If you are extracting/converting the video and audio from a MKV file to an AVI, first load the MKV into VirtualDubMod. Then follow the steps for using LameACM to compress your audio to MP3 as shown in EADFAG here: Using LameACM to Compress your Audio in VirtualDubMod, disabling any unneeded streams. Now go to File > Save As... The Save as type: should be AVI as default. Change the Video Compression settings as needed, then click Save.

At the worst case, you'd have to have VirtualDubMod output the audio as a WAV file and then re-import it into VDM, use the LameACM to compress it into MP3 audio then mux it into the final AVI file. OR convert the WAV to MP3 with BeSweet then mux it with VDM.

bah, it says it's a vorbis stream and i have to demux it. It wont let me do the compression or save as a wav. Are there any free audio converters i could use for ogg-wav/mp3? I don't think besweet can do that.